Al Qaeda in Iraq claimed responsibility Tuesday for a string of attacks that killed almost 70 people and wounded more than 200.

The seemingly coordinated explosions Thursday struck during the height of morning rush hour, hitting a number of Baghdad’s primarily mixed Sunni-Shiite neighborhoods. Nine car bombs, six roadside bombs and a mortar round all went off in a two-hour period, targeting residential, commercial and government districts in the Iraqi capital, police said.

“The series of special invasions launched, under the guidance of the Ministry of War in the Islamic State of Iraq, to support the weak Sunnis in the prisons of the apostates and to retaliate for the captives who were executed,” the group said on an al Qaeda website.

A recent political crisis has raised fears of a return of the sectarian bloodshed in Iraq that ripped the country apart at the height of the war a few years back. The political turmoil as well as the recent spate of violence erupted just days after the final U.S. troops withdrew.

Violence in Iraq has declined in recent years but last week’s attacks were among the worst since August when a series of coordinated bombings killed at least 75 people in 17 Iraqi cities.